I have a couple of 32 gig micro SD cards. They were formatted using SDFormatter software and used to install different versions of OpenElec on a Raspberry Pi. The PI appears to require an MBR partition and the the system formats the remainder of the card for storage etc. Since doing that, I can no longer format these cards. I've tried on OSX, Windows 10 and Mint. Their various systems say they're formatting but when they're done the file structure remains as it was pre-format. It's seems like the PI has locked the cards so they can't be overwritten. But the adaptor isn't in lock and the systems are read and write according to OSX. The closest I came to fixing the issue was with Mint, which indicated the two partitions had been deleted and then reformatted in FAT, but again when I plug the card into OSX or Win10 the two partition system remains.

I've plugged the cards into an ASUS tablet, a BLU smartphone and a Samsung Tablet. The Samsung doesn't 'see' the card at all and the ASUS and BLU see only the FAT partition of 855 MB. None of the 3 even offers the Format option. Anyone run into this and found a fix? I've googled every way I can think and can't find anything even approaching this issue.

My normal solution to this type of problem is wipe the mbr, create a new dos mbr, then partition it, & finally put a new file system on it.

That's probably what I'd try as well.

There's only one tiny problem, nothing will wipe the MBR. I tried 3 different OS's, Terminal, and SDFormatter on two different OS. Everything, except Terminal reports that the deletion has occurred and the formatting successfull, but nothing changes on the card. Terminal commands won't even run. PI even reports errors now, although it does see something as it's able to report the filesystem is broken.

You tried ?

To properly make an OpenElec.tv image

http://wiki.openelec.tv/index.php/HO...#tab=DiskImage

Use Gparted to remove all partitions. Really any OS that has access to partition program would do.
While it is possible that some older flash modules have a small switch that locks write it is unlikely there. You are for some reason not removing the partitions. OpenElec didn't lock anything.

It may be that the flash is locked somehow and may have an OEM program to recover it.
Sandisk sent me a program when they replaced a warrantied CF. Some are online for download.

It is possible it has gone bad.

I'm leaning toward it having gone bad, except that in Terminal diskutil will show it and list off the partitions. I did try to remove the partitions and reformat using diskutil with no luck. I'll see if I can find a flash program for this disk.
And Disk Utility will unmount the volumes.

I think the card is bad, after all the work in Terminal my Win 10 machine doesn't even recognize it's presence anymore.

What I don't understand is that OSX recognizes the card even though it's a FAT partition, but Windows doesn't. There are text files in the FAT partition that I can access, open and read using Finder suggesting the card isn't completely dead.

Windows will only (usually) see the first partition on some types of portable media.

SD cards can go bad. And tend to go bad in a READ ONLY mode. I've had a sandisk (not micro) one do that on me in under 4 hours. Installed linux, booted it, watched a couple youtube videos on it, and then it went south. Did a mkfs on the questionable partition and it contained all the old filesystem contents and was bootable, but as a usable device, toast.

# dcfldd if=/dev/zero of=/dev/sdX bs=4M
# dcfldd if=/dev/sdX of=image_of_sdcard.img bs=4M
$ hexedit image_of_sdcard.img

If it's not all zeros, then it's not write-able. You may still be able to write "some" parts of the device, but it's basically toast as a usable device. Where /dev/sdX is the actual device name for your card. I have two failed cards so far, all class 4 sandisk ones. All of my class 6 or better ones still function (to the best of my knowledge / not symptomatic). But most of my installs that run off of them are pretty static outside of logs and browser cache.